相关论文: The lack of rotation in a moving right angle lever

The absence of any tendency toward rotation in the Trouton-Noble experiment is given a simple explanation.

An extended body subject to external forces which exert zero net force and zero total torque in the rest frame, may experience a nonzero torque in another inertial frame, and nonetheless does not rotate. Long known as the Trouton-Noble or…

It is proved that the field of a gravitational lens induces no rotation in the polarization vector of electromagnetic radiation, in agreement with the previous literature, but with a different approach. The result is generalized to the case…

A skier's motion was analyzed by a simple model consist of point mass $m$ and a single rod connected to a single ski plate. We studied the conditions for the stable ski turn as functions of the linear velocity and the radius of the turn.…

It is well known that two permanent magnets of fixed orientation will either always repel or attract one another regardless of the distance between them. However, if one magnet is rotated at sufficient speed, a stable position at a given…

Every simple drawing of a graph in the plane naturally induces a rotation system, but it is easy to exhibit a rotation system that does not arise from a simple drawing in the plane. We extend this to all surfaces: for every fixed surface…

Within the framework of general relativity, in some cases at least, it is a delicate and interesting question just what it means to say that an extended body is or is not "rotating". It is so for two reasons. First, one can easily think of…

I show that no force or torque is generated in cases involving a charge and a magnet with their relative velocity zero, in any inertial frame of reference. A recent suspicion of an anomalous torque and conflict with relativity in this case…

If one is given a rigid triangle in the plane or space, we show that the only motion possible, where each vertex of the triangle moves along a straight line, is given by a hypocycloid line drawer in the plane, and a natural extension in…

A relative mechanics with no absolute space is shown to be equivalent to Newtonian mechanics applied in a universe of zero net angular momentum. Closed spaces in General Relativity have no angular momentum and shrivel to one point as the…

We prove here a long standing conjecture in general relativity, that if barotropic perfect fluid is moving in a shear free way, then it must be either expansion free or rotation free.

It is known that an object translating parallel to a soft wall in a viscous fluid produces hydro- dynamic stresses that deform the wall, which, in turn, results in a lift force on the object. Recent experiments with cylinders sliding under…

A rigorous, non-perturbative proof that there is no radiation damping of gravitational motions.

The mean force exerted upon a perfect mirror moving in vacuum in a two dimensional spacetime has the same expression as the radiation reaction force computed in classical electron theory. It follows that unacceptable runaway solutions are…

It is shown without making use of Lorentz transformation that there exists a phenomenon of relativistic zero-frequency shift in Doppler effect for a plane wave in free space, observed in two inertial frames of relative motion, and the zero…

We present a simple, two dimensional example of a "cat" -- a body with zero angular momentum that can rotate itself with no external forces. This model is used to explain why this problem is known to be a gauge theory and to illustrate the…

Using the complete Dirac Hamiltonian for a relativistic electron it is shown that the spin transverse force derived by S.Q. Shen, Phys. Rev. Lett. 95, 187203 (2005) does not exist. This force is an artefact resulting from an approximate…

A simple apparatus to demonstrate free fall weightlessness is given. This can be easily constructed from readily available materials and can be used for the demonstration purpose to an audidence with all the details of the apparatus…

The exact analytic solution is built for the plane flow of incompressible fluid through the wheel with profiles of blades approximating logarithmic spirals.

We here show that, even in the absence of "regularizing" microscopic effects (viz. slip at the wall or the disjoining pressure/precursor films), no singularities in fact arise for a moving contact line surrounded by the pure vapor of the…